Temperature effect of NMR surface relaxation in water saturated rocks

Key words:  nuclear magnetic resonance  water-saturated rocks  surface relaxation  temperature effect

Abstract:

Temperature is one of the factors which affect nuclear spin-relaxation in rocks. A series of water-saturated core samples including silica carbide, calcium carbonate, Berea sandstone and reservoir carbonate were selected to measure nuclear spin-relaxation from 25 T! to 90 'Xl. The results show that temperature effects on nuclear magnetic resonance( NMR) surface relaxation between water-saturated sandstone and carbonate are different. The nuclear spin-relaxation rate(1/T2) increases with temperature increasing for water-saturated silica carbide and reservoir Berea sandstone. Relaxation rate decreases with temperature increasing for water-saturated calcium carbonate and reservoir carbonate. The temperature effect should be taken into account while calibrating NMR logging data by using laboratory experiments performed at room temperature.